Muffler recommendations 1965 barracuda 273 original exhaust manifolds.
Dynomax superturbo would give you what you want. And as
@65dartcharger says a factory hi-po single exhaust would also sound good and perform just as well in your 2 barrel car. You wouldn’t have to modify the transmission cross member too.
‘’check out accurate exhaust and look for Formula S exhaust. may not be cheap though.
‘’if you do duals modify the trans crossmember to get the pipe up nice and high.